It has long been known that certain biologically active substances can be obtained from the glands of animals and the substances so obtained utilized in the treatment of deficiencies of the human body. One such substance is the adrenocorticotropic hormone, commonly called ACTH, which for many years has been obtained from the pituitary glands of animals, particularly porcine and bovine pituitary glands.
For many years the art has eargerly awaited the discovery of more practical methods and compounds which enable the commercial synthesis of such peptides from other than natural sources. One such synthesis is set forth by Colescott, Kaiser, Bossinger and Cook in the U.S. Pat. No. 3,915,949 dated Oct. 28, 1975.
The solid phase synthesis set forth in that patent utilizes insoluble polystyrene resin which is prepared by catalytic polymerization of styrene and divinyl benzene and this is chloromethylated using chloromethyl ether and stannic chloride catalyst.